I've been a Singed main for four seasons now. I've played him since he was 42% winrate trash-tier trollpick. Playing this champion now doesn't feel any different from back then. What the OP (and most people that make these kinds of massive QQ salty rants) don't ever seem to consider is team composition, playstyle, and denying the Singed early. Singed's counterplay is pretty clear - spam some normal games and you'll see it.
Singed gets denied fairly hard in lane by matchups that can zone him with range such as
. Singed's early game is god-awful pre-6 with the exception of level 2 all-in. His health pool is low, his base resists are low, and to be able to last hit, Singed must position within melee range of the creeps (and harass range of his opponent.) If you're using poison trail to try to shove and avoid harass, you need to be on the enemy wave and will eat a shit ton of harass. Singed also naturally pushes the lane while trading with his opponent, making him extremely vulnerable to ganks pre-6. Call your jungler for the free kills.
Most of Singed's good matchups in lane are melee tanks that can't kill him. Picking
etc into Singed isn't "safe" like it is into most other top laners. You'll have absolutely zero kill pressure on him and Singed will just farm for free. Singed is a mid-game powerhouse and if your mindset is to play safe into him you're approaching the matchup entirely wrong. You need to kill him, deny him CS in lane, and abuse his weak pre-6.
Champions like
are all melees that Singed cannot fight in lane unless they make a mistake, in which case it's the player's fault. They all have much higher priority in the lane and can zone Singed starting at level 1.
Given that Singed isn't as easily able to itemize magic penetration as he was before the changes to AP items, items such as
are EXTREMELY effective against him in lane. Buying an early hex/cowl shuts down any sort of potential to trade that Singed has. Grievous wounds
are a must-have in your team as most of Singed's mid-game tankiness comes from health regen on his ultimate.
Picking champions like 
into Singed is extremely effective - to be able to teamfight against a Singed you must treat him like a hybrid diver. Chain CC him when he comes close and blow him up - with the aforementioned grievous wounds items he'll be unable to regen and a 3 item ADC can shred him.
"But what about the proxy farming? I hate it and it's not interactive!" Buy
etc and face tank the wave. It's not worth it to go chase him unless you can guarantee a kill. Singed is either proxying to farm without being harassed or to shove the lane and draw pressure. If you hold the tower, you cancel him out and get the entire creep wave as well. Walk your creeps to lane at level 1 to avoid an early proxy, Singed cannot tank the wave if you harass him and he'll have to back off or recall. If you chase him, waste time on him, that's exactly what a good Singed wants to do and he'll be spam pinging his team onto objectives while you waste all your time on a side lane trying to chase him down.
If you think you can play against Singed the same as you would any other champion, you're entirely wrong and deserve to lose the game. Riot has him marked under "Unique" class for a reason. His playstyle is entirely different from other champions and you have to adjust how you play against him to reflect that. Singed scales with AP and tank stats. Singed also scales with his opponents' stupidity. If you play carelessly against him, you're going to be punished.